In some instances servers store multiple versions of a sequential dataset, such that they can provide current, earlier and/or later versions of the sequential dataset to clients. A sequential dataset comprises a set of data that changes over time as content is modified, added or deleted. Each time content changes, most of the data in the set remains the same, but some portion is updated. For example, think of a server managed by a publisher of security software storing malicious code definitions. Because new malicious code definitions are added frequently as new malware is identified, the current set of malicious code definitions is frequently changing. To provide an updated dataset to a client (i.e., in this case the current set of malicious code definitions where the client has an earlier, non-current set), such servers conventionally generate a direct delta between the target set (e.g., the current version of the malicious code signature set) and the version of the dataset currently stored locally by the given client. The server then provides the delta over the network to the client computer. However, in case of an error or problem with the update, it is important that the client be able to restore an earlier version of the sequential data that was known to work reliably. Thus, the server conventionally caches the full file set of each version of the sequential data it needs to make available to a given client. However, full file sets can be quite large. This means that for each version of a typical set of malicious code definitions cached by the server, a large amount of storage space is used. Depending upon the nature of the business, a customer might have 1 to 20 GB of server space for caching definition sets. However, considering the large size of the full data sets, this gives the customer only enough space to store direct delta coverage for a short time (e.g., one to ten days or so). Customers of security software would typically like to have more coverage. This matters to customers because distributing full, malicious code definitions to each node within their organization can saturate their network and effect business operations. Therefore, it is important to be able to distribute deltas rather than full definition sets, even when the nodes within the organization have not been updated recently (e.g., because of a holiday). It would be desirable to be able to provide customers with 45 days of direct delta coverage, by default, in order to support 30 day European holidays. With conventional technology, however, the space consumption is well beyond reasonable. It would be desirable to address these issues.